Conventionally, as a ceiling fan of this kind, a ceiling fan has been known in which stationary blades whose elevation/depression angle for changing the wind direction is rotatable are disposed at the downstream side of rotating blade plates radially arranged on the outer periphery of an electric motor (see, for example, Patent Document 1).
Hereinafter, the ceiling fan is described with reference to FIGS. 17A, 17B, 18A, and 18B. FIG. 17A is an external perspective view showing a conventional ceiling fan, and FIG. 17B is an external top view showing the ceiling fan. FIG. 18A is an external side view showing a principal part of the ceiling fan, and FIG. 18B is an external side view showing an air flow of the ceiling fan.
As shown in FIGS. 17A to 18B, a plurality of blade plates 107 are radially disposed on rotor 105 incorporating electric motor 104 (see FIG. 18B). A plurality of plate-shaped stationary blades 110 fixed to non-rotating portion 106 are disposed in a lower part of blade plates 107. With such a configuration, as shown in FIGS. 18A and 18B, since a pressure is increased by collecting the kinetic energy of circumferential direction component 114 of blown air 113 flown out of blade plate 107, the air blowing efficiency can be improved. Furthermore, by changing the rate of circumferential direction component 114 and downward component 118 of blown air 113, the arrival range of blown air can be changed.
In this way, in a conventional ceiling fan, in order to adjust an air current from moving blades such as blade plates 107, a plurality of stationary blades 110 may be provided at the downstream side of the moving blades. In such a case, when elevation/depression angle θs of each stationary blade is changed, a plurality of driving motors are required. Alternatively, when one driving motor is used, a plurality of gears for converting and transmitting a rotation torque of one driving motor are required. Therefore, in any case, a number of components to be used for transmission is increased, thus complicating the structure. Furthermore, when repeated load of blown air is applied from the moving blade to stationary blade 110 for a long time, a fatigue failure occurs in the vicinity of the root of stationary blade 110, and the stationary blade may be broken. Thus, when the stationary blade is broken, stationary blade 110 may drop off.    [Patent Document 1] Japanese Patent Application Unexamined Publication No. 2007-198337